GHCJS

Hi,
>> So perhaps that's the problem. parseDynamicFlags could perfectly well simply return any un-recognised flags. Indeed, I thought it did just that -- it certainly returns a list of un-consumed arguments. If it doesn't perhaps that's a bug.
>> parseDynamicFlags returns un-consumed arguments if they are something
> like filenames, but it throws error if un-consumed argument starts
> with dash.
Maybe you can wrap the GHCJS into a plugin now that plugin support is finally in GHC 7.2.* , and generate the javascript as a side-effect [1]?
Then you can pass option specifically to GHCJS using the '-fplugin-opt' command line option.
Cheers,
Christiaan
[1] It is my understanding that plugins can only do Core-to-Core passes